WO 2004/057927 discloses a method for configuration a wireless controlled lighting system. The prior art system comprises a central master control device, several local control master devices, which are linked to the central master device, and, associated with each local control master device, one or more lighting units and a portable remote control. Each lighting unit and the portable control are linked to their associated local control master device by a wireless connection. Light emitted by a lighting unit is modulated by an identification code, which was stored in the lighting unit before controlling the lighting unit. The portable control is suitable to receive the modulated light and to derive therefrom the identification code of the source lighting device. The portable control has an user interface by which an user can enter additional data, which is sent to its associated local control master device together with the identification code received from a lighting unit. Said additional data may contain an indication of a switch or key which the user assigns to the lighting unit to operate the lighting unit from then on, such as for turning on or off. Then, the data is communicated to the central master device for general lighting management.
With the prior art method and system the control of lighting units is carried out by forward control only, that is, without any kind of feedback about actual lighting conditions and locations of the lighting units. For example, an object can be illuminated by any number of lighting units directly, but also indirectly as a result of reflections. With the prior art system it is not possible to measure lighting effects caused by different lighting units on an object and to change controlling of the lighting units dependent on the measured lighting effects.
Further, the inventor considered that it could be a great improvement for certain applications if the portable unit could be used by the user like a mouse of a personal computer for tracking and dragging a light effect caused by the lighting units. Such feature is not disclosed by any reference known to applicant.